Even if your Twitch account and ESO account were successfully linked before, they can become unlinked, so if you don't get a drop as expected then you would be well advised to go through the motions of relinking them again just to be sure.

Also, your "presence" on Twitch needs to be set to "online" rather than "invisible" or "busy," and the "share my activity" option should be enabled. I've noticed that the Twitch app on my Windows 10 computer seems to always start up with those settings mucked up, so I have to change them back every single time I watch Twitch on my desktop. But the Twitch app on my iPad seems to keep those settings intact-- except I did notice that they had gotten mucked up just the other day and I had to set them back to "online" and "share my activity" again. I'm not sure why they suddenly got mucked up, unless it was because of the iOS update that I installed the other day.